Simplified estimation of glomerular filtration rate and effective renal plasma flow.
A method is described for the determination of GFR and ERPF using a combined injection of 51Cr-EDTA and 125I-iodohippurate. Plasma samples obtained at 60 min and 150 min after administration were used to determine a flow rate F assuming a monoexponential clearance of the tracers. Empirical relationships were found between F and the true GFR and ERPF determined from multiple sampling and multi-exponential analysis of the clearance curves. The method was shown to be superior to previously published methods involving one or two samples. GFR was calculated with a standard deviation (SD) of only 3.3 ml/min when compared to the multiple sample technique (the reference method), whereas the best estimate from a single sample had a SD of 6.3 ml/min. An improvement in accuracy of ERPF estimation was achieved for values of flow of less than 200 ml/min when the SD was only 9.3 ml/min.
D002860:Chromium Radioisotopes; D004492:Edetic Acid; D005919:Glomerular Filtration Rate; D006801:Humans; D007465:Iodohippuric Acid; D007668:Kidney / Q000098:blood supply*; D011866:Radioisotope Renography / Q000379:methods*; D012039:Regional Blood Flow
D002860:Chromium Radioisotopes; D007465:Iodohippuric Acid; D004492:Edetic Acid